Earlier this week, a supremely rare and historically significant piece of Fender history dropped into the pages of Reverb in the form of a listing for an original Jazz Bass prototype from 1959. As is often the case with a unique instruments like this, the listing landed on a few forums and Facebook groups, where amateur experts discussed its provenance, price, and place in gear history.

Looking at this Jazz Bass — with its peculiar Jazzmaster–like pickups — I was reminded of the many other intriguing gear prototypes that have wound up on Reverb in the past. Instrument development is, after all, an iterative process, and the path to a luthier or engineer's eventual success is usually paved with a series of false starts.

More often than not, these pre–production pieces are perfectly functional and invite us to infer a lot about the design process and make all sorts of counterfactual hypothesis on what could have ended up a different way.

Prototypes present a fascinating sub–section of the rarest gear on Reverb, and one that we thought we'd take some time to explore today by presenting 10 of the coolest prototypes currently listed on the site.

Fender 1959 Jazz Bass Prototype

Any instrument touched by a vanguard like Leo Fender deserves a place on this list. Any instrument that laid the groundwork for an entire genre of instruments should be at the top of this list, so we’re starting with the aforementioned Fender Jazz Bass prototype.

Verified by Master Builder Jason Smith of the Fender Custom Shop, this Jazz Bass appears in multiple books on Fender history and provides a tangible view into the process of a visionary.

The two most standout details about this bass are the pickups and the control knobs. On the production Jazz Bass that launched in 1960, the controls were in a concentric configuration with volume and tone stacked into a pair of two–part knobs.

This bass shows the three–knob configuration that became standard a couple of years later. The pickups, while likely similar to the eventual production models found on later instruments, feature wide plastic coverings, much like the Jazzmaster introduced in 1958.

Fender 1983 Neck-Through Stratocaster Prototype

At first glance, you might think you’re looking at a B.C. Rich or Ibanez with a different headstock, but make no mistake: this is all Fender.

Made during the Dan Smith years when the exec was breathing life back into the company, this 1983 neck–through Strat prototype sees a familiar shape paired with not–so–familiar features, like a black walnut winged body, gold accent humbuckers and white cross fret inlays, and a neck–through design meant to compete with the evolving “Super Strats” of the era.

Teletronix LA–2 Prototype

Teletronix founder Jim Lawrence revolutionized the recording industry when he pioneered the use of photocells for managing gain the in early ‘60s. A radar operator during WWII, Lawrence concocted the ideal photocell mixture for a leveling amplifier in the LA–1 (only around 100 were made) and further improved on the recipe with the LA–2.

This LA–2 prototype — featuring the build of an LA–1 with definitive LA–2 features, like the larger VU display — typifies a masterpiece in progress.

Ampeg Dan Armstrong Lucite Bass Prototype

While Airline and the Res–O–Glas models were one of the first instances of guitars made from materials other than wood, Dan Armstrong and his see–through Lucite instruments became an instant classic. This pre–production bass from 1967 features unique routing and cutaways distinct from the standard model. An early iteration of a maverick instrument.

Fender Billy Corgan Signature Stratocaster Prototype

As you may have seen already, we recently launched an official shop with Billy Corgan stocked with a staggering array of historic gear from his collection. Included in this bounty were a handful of prototypes of Corgan's signature models, including this original Strat from Fender. Of note, this guitar uses an early usage "baked maple" for its fretboard.

Pre-serial Ludwig Acrolite Snare

While the Black Beauty and Supraphonic get most of the attention in the Ludwig snare roster, the Acrolite developed a devoted legion of fans for its crisp attack and coveted ghost notes.

Originally introduced as a student model snare, the Acrolite was quickly recognized for its solid build and tonal character. This prototype features a bare aluminum shell without the iconic matte finish and pre–serial badge.

EMS Synthi E Prototype

Part modular synthesizer, part briefcase, and all legend, the Electronic Music Studios Synthi played a vital role in miniaturizing behemoth modular synths and making modular synthesis accessible to a broad audience.

The Synthi E was the company’s educational model, designed to offer newcomers a streamlined experience to build familiarity at a time when synths were still foreign territory for many. This one–of–a–kind model easily earns the title of “museum–worthy.”

Travis Bean TB2000 Bass Prototype

Travis Bean guitars and basses have earned a serious cult following with a particular group of modern metal and indie rock players, most of whom laud the unique tone and playability afforded by the combination of a koa body and aluminum neck.

This particular bass — serial number 0 — is much like the other Travis Bean basses produced during the company's original run from 1974 to 1979, but with a slightly different style on the neck joint.

Paul Reed Smith Pre-Production Guitar 1979

In the first era of PRS' history, all guitars were handmade by Mr. Smith himself, so the term "prototype" may not be entirely accurate.

This particular 1979 build, however, is apparently the first PRS to sport a single–piece maple top with a sunburst finish, making it an especially noteworthy stepping stone in the brand's evolution. The pickups on this guitar are actually Gibson P90s that Paul rewound for this instrument.

Fender 1965 Coronado

The Fender Coronado — helmed by noted Fender designer Roger Rossmeisl — was never much of a success, and judging by a few early models we've seen over the years, experienced some design setbacks when it was originally conceived.

This early example is a good example, and as seller True Vintage Guitar points out, there's even a "...rather crude aluminum dowel in the neck pocket likely to provide strength to a potentially weak bolt on hollowbody–style joint."